Manufacture of printing blocks



March 3, 1936. Q 5 HASSING 2,032,75

MANUFACTURE OF PRINTING BLOCKS Filed Dec. 7, 1951 2 Sheets-Sheet l 63 I Om? Siniusfiaaina 64- v 27 INVENTOR- KM Attorney,

March 3, 1936. 0. s. Assume.

MANUFACTURE OF PRINTING- BLOCKS Filed Dec. 7, 1951 2 Sheets$heet 2 Patented Mar. 3, 1936 UNITED STATES PATENT OFFICE Application December 7, 1931, Serial No. 579,575 In Denmark January 16, 1931 9 Claims.

The present invention relates to the manufacture of printing blocks and has for its object to accelerate and cheapen such manufacture.

Another object of the invention is to produce 5 such printing blocks by pure mechanical operation on a plane or cylindrical blank, thus avoiding the necessity of preparing intermediate objects which are essential in the commonly used processes for this purpose in which etching of the blanks is effected. Printing blocks produced by the present invention possess all the advantages of mechanically produced blocks, especially because underbiting by etching is avoided.

It has been proposed heretofore to mechanically produce printing blocks by operating on the blank 1 with a tool cutting parallel grooves of varying depths into the blank, the depth and width of the grooves varied by electrical means in accordance with the tone of an original. This procedure,

20 however, has the serious drawback that the tool is constantly in the cutting position and will therefore very forcibly oppose any adjustment. In consequence the printing block produced will not be similar to the original.

The principal object of the present invention is to obviate this drawback and this object is attained in that the tool is only caused to operate on the blank point after point, in such a manner that the operating depth can be adjusted while the tool does not operate, whereby the adjustment can be effected without any disturbing resistance.

For the purpose of the present invention it is immaterial whether the original be an opaque or a transparent picture, an object occurring in nature 5 or a person, or whether it be represented by the variations in current received by picture transmission (picture telegraphy).

If the original is an opaque picture, the lightsensitive cell may be actuated by the light reflected by the spot of light from the surface of the picture.

The displacement of the spot of light may be effected either by motion of the original or by displacement or rotation of the source of light or by a combination of both, and the displacement of the operating point on the blank may be effected either by displacement of the blank or by displacement of the operating apparatus. If a combination of displacement of the original and 5c of the blank is used, the original and the blank are disposed on a common supporting member. The motion may also be effected when the original and the blank are disposed each on a separate supporting member. This last mentioned pro- 55 cedure offers the possibility of effecting simultaneously with the reproduction a change of scale, the linear displacements of the original and the blank between two consecutive points respectively between two consecutive workings, being then not of the same length.

In general the simplest way of attaining the desired variation in the width of trace or cutting will be to use an operating tool with a triangular operating end, for instance a graver with wedgeshaped profile, in such a manner that the ratio of the depth of operation to the width of trace or cutting will be linear. If this is the case the depth of operation for each individual cut will be directly dependent on the amount of light received by the light-sensitive cell from the corresponding point of the original. It will further be evident that the distance between the individual operating points on the blank will correspond to the screen division, so that the finished printing block may be used directly for printing of tone-pictures.

A simple apparatus embodying the present invention comprises a mechanism tending to move the operating tool forward intermittently by strokes of uniform length, and interposed between the driving mechanism and the tool proper is an adjusting member the position of which determines how great a portion of the given length of stroke of the driving mechanism will be transmitted to the tool proper. Such an adjusting member may consist of a wedge, a series of steps or the like adapted to be pushed forward and backward by an electromagnetic driving device actuated by an amplifier, or by a helical surface or stepped surface or the like rotated by such a device.

The outstanding advantage obtained by the present invention as compared with prior art procedures is that the printing block can be produced directly from the original, without the necessity of preparing intermediate objects, so that the manufacture can be finished a small fraction of the time heretofore required for the manufacture of printing blocks. Not only the time thus saved, which is valuable in the manufacture of printing blocks for newspapers, shows the superiority of the present invention, but equally important is also the saving of material, which enables such printing blocks to be produced far more cheaply than heretofore. It should further be pointed out that printing blocks produced according to the present invention possess all the advantages of mechanically prepared printing blocks in general relatively to those prepared by etching, especially because underbiting is thus avoided.

The invention is illustrated in the accompanying drawings, in which Fig. 1 shows diagrammatically the manner in which a printing plate is produced with my improved apparatus,

Fig. 2 shows a side view of the apparatus, and

Fig. 3 a section on the line IIIIII in Fig. 2.

Referring to the drawings, and particularly to Fig. 1, a shaft I, which is journaled in bearings 2, supports a disc 3 having holes 4 and can be set into rotation by a motor 5. By way of the holes 4 a source of light 6 directs light to a lens system I, which condenses the light from the source to a spot of light 8 on the surface of an original 9,

from which a printing block is to be produced. In the case shown the original is supposed to be opaque.

The original is disposed on a supporting member Ill, which by means which will be explained below, can be displaced in two directions in its own plane, in such a manner that the spot of light 8 can successively cover, point after point, the entire original 9.

In many cases the supporting member l may suitably be shaped as a plane table which may be displaced in two directions by any suitable means. In the case of originals of flexible material a simplification of the construction of the apparatus may in many cases be attained by giving the supporting member ill the form of a cylinder adapted to be rotated about its axis aswell as to be displaced axially. In other cases it will be suitable to be able to move the source of light 5.

The spot of light 8 impinging on the original 9 causes the original to emit light the intensity of which depends on the color of the point upon which the spot of light impinges. Much light will be emitted if the spot of light impinges upon a white or light part of the original, while only little or no light will be emitted if the spot impinges upon a black or dark portion of the original. The light thus reflected impinges upon a light-sensitive cell H, which by wires l2 is connected to an amplifier device l3, which is not shown in detail but by wires M is connected to an electromagnetic driving device !5 shown diagrammatically in Fig. 1 as an electromagnet between the poles of which an armature i6 is disposed. As indicated on the drawings by means of dotted lines the light-sensitive cell 1 I may be of annular shape. The armature I6 is guided in two sleeves IT, a spring l8 tending to pull the armature away from the electromagnetic driving device l5. The armature supports an adjusting member l9.

On the drawings the adjusting member is shown to be a wedge, but as mentioned above the member may be stepped or may be shaped as a helical surface acting by rotation instead of by displacement as shown here. Above the adjusting member I!) a driving device 2! is provided which in Fig. l is constructed as an eccentric disc, supported by a shaft 2 l. Below the adjusting member I 9 the operating tool is disposed, which in the construction shown comprises a pushbar 23 adapted to move up and down in a fixed sleeve 22 and fitted at top with a shoulder 24 against which one end of a spring 25 abuts,

while the other end rests on a part in rigid connection with the sleeve 22 and, therefore, tends to lift the pushbar 23 up against the adjusting member l9. To the bottom end of the pushbar 23 the operating tool 25 proper is attached,-

which may for instance be a graver with triangular cutting edge. Below the graver the blank 21 intended to be converted into a. printing block is attached to a table 28 adapted to be moved in a similar manner as the table I0.

Figs. 2 and 3 show how the apparatus may be constructed.

On a frame 29 two longitudinal guide rails 30 are provided, on which the tables 31 are adapted to slide. Between the rails 38 nut members 32 project from the tables 3! and engage the corresponding screws 33 and 34, which are journaled in the frame 29 and are interconnected by means of a gear box 35, in such a manner that they can be rotated at the same or different speeds.

The tables 3| are fitted with beds 36, on which the tables H] and 28, respectively, can slide.

The lower faces of tables I0, 28 engage threaded spindles 31 supporting ratchet wheels 38 adapted to be rotated by means of levers 39, which are pivotally suspended on the spindles 3'! and are fitted with pawls 4i] engaging the ratchet L Wheels 38. Springs ll tend-to maintain the levers 39 swung to the right in Fig. 2. The levers are interconnected by means of a connecting rod 42, one end of which is pivoted to one of the levers 39 by means of an adjustable link member 43, while the other end of the rod is connected to the other lever by means of a fixed link member 44.

The screw 34 is rotated by pulleys 55, viz two fixed and one loose pulley engaged by an open and a crossed belt adapted to be shifted by means of a belt shifter 46 operated by one of the levers 39.

By means of bevel gears 41 the screw spindle 34 is connected to an intermediate shaft '58 which by bevel gears 49 is connected to the shaft 2!, in such a manner that the latter will be rotated together with the screws 33 and 3t.

The drawings show how the motor 5 is suspended to a supporting frame 50, and how the lighting device may be constructed.

Two lamps 6 are used, the light from which is concentrated by the condenser lens 7 to the spot of light 8, and a microscope objective 51 forms on the light-sensitive cell H an image of the said spot, which image is limited by an adjustable diaphragrn 52, in such a manner that the effective size of the spot of light can be varied in a simple manner.

The amplifier I3 may be disposed on the apparatus or outside of the same, and may for instance be suspended from the ceiling above the apparatus.

As it is of the greatest importance for the quality of the finished printing block that the cuts produced by the tool 26 in the blank 27 should only depend on the current impulses received by the electromagnetic driving device I5 from the lighting device, but not on any casual variations in the thickness of the blank, an arrangement is used for elimination of errors produced by such variations in thickness.

This arrangement is illustrated in Fig. 3. Below the driving device Zil a plane-parallel block 53 is disposed which is supported by a plate spring 54- held rigidly in a fixed arm 55 on a plate 56 carried by'arms 5'! (Fig. 2) which support the entire tooling device and are rigidly connected to the main frame 29.

The plate 56 is fitted with a pivot pin 58 for a bell-crank lever 59 one shorter arm of which is hinged to a rod 50, which by means of a pin BI' is hinged to thelonger arm of a two-armed lever 62, and the latter is pivoted about a pin53 in a bracketli l onthe sleeve'22. The shorter arm of thislever'62 is fitted with a feelerpoint 64 the lower end of which rests on the top surface of the blank 21 next to the tool 26 and is held pressed against the blank by means of a spring 65.

The other shorter arm of the bell-crank lever 59 supports a plate spring 66, the free end of which carries a wedge 61, which is situated between the block 53 and the adjusting member I9.

The apparatus operates in the following manner:

The motor 5 rotates the shaft I and causes the holes 4 to come successively into range of the rays of light from the source of light 6, in such a manner that intermittent spots of light 8 will be emitted to the light-sensitive cell II, the nature of such light depending on the spot of light 8 impinging upon a light or dark part of the original 9.

At the same time the screw spindles 33 and 34 will be rotated from the countershaft 48 and the tables 3| will move simultaneously along the rails 30, either at the same or at different speeds, depending on the adjustment of the gearbox 35.

Whenever the tables 3| are moved all the way to one side one of the levers 39 will shift the belts .of the pulleys 45 and will cause the direction of revolution of the machine to be reversed. At the same time the levers 39 will move the ratchet z"; wheels 38 in such a manner that the tables I 0 and 28 will be moved one step sideways along the beds 36.

In a manner known per se the current controlled by the light-sensitive cell will vary, and

. by means of the amplifier I3 the said variations will be transmitted in amplified condition to the device I5, in such a manner that the intensity of the power with which the said device actuates the armature I6 will vary synchronously with the variation in intensity of the light reflected from the spot of light 8 to the light-sensitive cell I I.

The position of the armature I6 will therefore be dependent on this intensity of light. In consequence thereof the position of the adjusting member I9 will also be dependent thereon.

In the example shown in Fig. l of the drawings the conditions are assumed to be such that a powerful light, corresponding to the spot of light 8 impinging upon a light part of the original 9, will cause a decrease in the attraction of the armature I6 by the device I5 and, consequently, will permit the spring I8 to pull the armature I6 away from the device I5 in such a manner that the thicker part of the adjusting member I9 will come below the driving dev ce 20 for the pushbar 23. In consequence hereof a light spot on the original 9 will cause the graver 26 to be depressed deeply into the blank 21, to make a wide out therein and, consequently, to leave intact only a smaller portion on the printing surface, that is to say a reproduction will only give small colored spots at the corresponding place. Vice versa, if the spot of light 8 impinged upon a dark part of the original 9, then the armature I6 and, consequently, the adjusting device I9 will be pulled towards the left, and the driving device 20 will only be able to depress the graver 26 slightly into the blank 21, in such a manner that a wide printingsurface will be left and, consequently, the reproduction will show large colored spots.

In the construction shown in Figs. 2 and 3 the conditions are reversed.

As the power required for driving the tool 26, in the construction shown in Figs. 2 and 3, is transmitted by way of the block 53 and the wedge 66 to the adjusting device I9, the position of the wedge 66 will also determine how far the graver 29 will penetrate into the blank 27. If the feeler point 64 meets a low part of the blank it will descend somewhat, and the lever 52 will push the link-rod 60 upward and cause the lever 59 to swing in clock-wise direction about the pin 58, in such a manner that the wedge 61 will be pulled farther under the block 53, and cause the graver to be moved farther down.

If the ratios of lengths of arms of the levers 6 and 59 be A and respectively, and the slope of the wedge be it will be feasible, in this manner, to attain the resultthat the graver 25 will always make uniformly deep cuts in the blank 21, for any 1 given position of the adjusting member I9, independently of any inaccuracies in the thickness of the blank.

As mentioned before, the driving mechanism 20 may be replaced by other devices acting in corresponding manner and, similarly, instead of the graver 26 other cutting tools, such as drills, cutters, grinding stones and the like, may be used. It is of importance, however, for the use of the tool that the width of the out can be varied in accordance with the tone of the original. If the material of the blank permits, there may also be used tools acting by direct impression, for instance punches or the like.

If the reproduction is to be full-size, the blank 21 may be disposed on the same supporting member I 8 as the original 9. If on the other hand a reproduction to other scales is desired, the supporting member 28 must be independent of the table I 0 as shown in Figs. 2 and 3, and must be I moved a different distance between the screen points than between the points illuminated on the original.

In the manufacture of printing blocks from a transparent original as a starting point the light- 5 sensitive cell I I may be disposed on the other side of the original, in such a manner that the work can be done by rays of light passing through the original. Otherwise no change of the arrangement will be involved. Similarly it will be possible 4 by use of methods known in photography to produce a printing block directly from an object or person standing free in space, the source of light 6 being then replaced by the light emitted from various parts of the object. to combine the printing-block tooling mechanism and the amplifier with a receiving device for wireless transfer of pictures, so that a printing block may be produced directly therefrom.

By use of monochromatic light or color filters it will be practicable to separate the individual colors from the original and, in this manner, to produce blocks for color-printing.

I claim:

1. Apparatus for purely mechanical manufacture of printing blocks from a blank and starting from an original, comprising the combination of an operating tool, mechanical driving mechanism adapted to impart to said tool a reciproeating motion with strokes of uniform length, and

means interposed between the driving mechanism and the tool and participating in the movement of the tool to adjust the mean position of the tool, said means controlled by amplified electric current impulses and adapted to transmit the movement of the driving mechanism to the tool.

2. Apparatus for purely mechanical manufacture of printing blocks from a blank and starting from an original, comprising the combination of a graver having a triangular operating end,

Finally it is possible a pushbar supporting the g'raver, the said pushbar being movably supported in a sleeve, a spring adapted to maintain the pushbar lifted in the sleeve, a driving mechanism adapted to impart to said pushbar and graver a reciprocating motion with strokes of uniform length, an adjusting device adapted to be controlled by amplified electric-current impulses and inserted between the push bar and the driving mechanism to form an operative driving connection therebetween, so as to participate in the movement of the tool and to adjust the distance between said uniform driving mechanism and said push bar thereby to adjust the operating depth of said uniformly reciprocated tool.

3. Apparatus for purely mechanical manufacture of printing blocks from a blank and starting from an original, comprising the combination of an operating tool, an eccentric disc, adapted to impart to said tool a reciprocating motion with strokes of uniform length, an adjusting device adapted to be controlled by amplified electriccurrent impulses and inserted between the tool and the disc to form an operative driving connection therebetween, so as to participate in the movement of the tool and to adjust the distance between said disc and said tool thereby to adjust the operating depth of said tool.

4. Apparatus for purely mechanical manufacture of printing blocks from a blank and starting from an original, comprising the combination of a graver having a triangular operating end, a pushbar supporting the graver, the said pushbar being movably supported in a sleeve, a spring adapted to maintain the pushbar lifted in the sleeve, a driving mechanism including an eccentric disc adapted to impart to said pushbar and graver a reciprocating motion with strokes of uniform length, an adjusting device adapted to be controlled by amplified electric-current impulses and inserted between the push bar and the driving mechanism to form an operative driving connection therebetween, so as to participate in the movement of the tool and to adjust the distance between said uniform driving mechanism and said pushbar thereby to adjust the operating depth of said uniformly reciprocated tool.

5. Apparatus for purely mechanical manufacture of printing blocks from a blank and starting from an original, comprising the combination of an operating tool, a driving mechanism adapted to impart to said tool a reciprocating motion with strokes of uniform length, a member of varying thickness in one direction and movable at right angles to this direction and disposed between the tool and the driving mechanism so as to form an operative driving connection between said mechanism and tool, to participate in the movement of the tool and to adjust the distance between said mechanism and tool there by to adjust the operating depth of the latter, an electro-magnetic driving member with which said member of varying thickness is mechanically connected and an amplifier adapted to receive primary electric impulses from a light sensitive cell responsive to light, modulated by the original electrically connected with said electro-magnetic driving member.

6. Apparatus for purely mechanical manufacture of printing blocks from a blank and starting from an original, comprising the combination of an operating tool, a driving mechanism adapted to impart to said tool a reciprocating motion with strokes of uniform length, an adjusting device adapted. to be controlled by amplified electriccurrent impulses and inserted between the tool and the driving mechanism so as to form an operative driving connection between said mechanism and tool, to participate in the movement of the tool and to adjust the distance between said mechanism and tool thereby to adjust the operating depth of the latter, said adjusting device including a wedge inserted between the driving member and the tool, and means for moving said wedge in accordance with the thickness of the blank.

'7. Apparatus for purely mechanical manufacture of printing blocks from a blank and starting from an original, comprising the combination of an operating tool, a driving mechanism adapted to impart to said tool a reciprocating motion with strokes of uniform length, means interposed between the driving mechanism and the tool and participating in the movement of the tool to adjust the mean position of the tool and the operating depth of the latter, a table for an original movable in two directions in one and the same plane, a support for the blank movable with the table in the predetermined manner of the latter, a lighting device for illuminating the original, a light sensitive cell responsive to said lighting device by light reflected from or modulated by the original and an amplifier connected to the cell to amplify the operation thereof and to provide amplified electric current impulses to control said means.

8. Apparatus for purely mechanical manufacture of printing blocks from a blank and starting from an original, comprising the combination of an operating tool, a driving mechanism adapted to impart to said tool a reciprocating motion with strokes of uniform length, an adjusting device adapted to be controlled by amplified electriccurrent impulses and inserted between the tool and the driving mechanism, so as to form an operative driving connection between said mechanism and tool, to participate in the movement of the tool and to adjust the distance between said mechanism and tool thereby to adjust the operating depth of the latter, a support for a blank movable in two directions within operating range of said tool, said support being disposed in such a manner, that the tool can operate on the blank throughout the entire surface thereof.

9. Apparatus for purely mechanical manufacture of printing blocks from a blank and starting from an original, comprising the combination of an operating tool, a driving mechanism adapted to impart to said tool a reciprocating motion with strokes of uniform length, an adjusting device adapted to be controlled by amplified electriccurrent impulses and inserted between the tool and the driving mechanism, so as to form an operative driving connection between said mechanism and tool, to participate in the movement of the tool and to adjust the distance between said mechanism and tool thereby to adjust the operating depth of the latter, a table for an original movable in two directions in the same plane and a support mechanically connected thereto for a blank within operating range of said tool, the connection between the table and the support being arranged in such a manner, that they are adapted to be moved synchronously, but at adjustable relative velocities.

OLUF SDIIUS HASSING. 

